Journal of Machinery Manufacture and Reliability最新文献

Methods of mathematical planning of a multifactorial experiment and processing of the obtained results are used to study the dependence of the optimization parameter—the size of the ground grain—on the rotor speed and the gap between the rotor and the stator. Based on mathematical calculations, a regression equation was obtained in the form of a first- and second-order polynomial, characterizing the contribution of each factor to the process of grinding grain products in conical-rotor mills.

Alloys with shape memory based on TiNi are characterized by maximally high characteristics of shape memory and superelasticity, allowing them to be used as implants for various purposes. The enhanced functional properties of the alloys are attributed not only to their physical nature but also to their microstructure, where it is desirable to have grain sizes in the nanostructured range. A new method for obtaining nanostructures based on plastic deformation accompanied by an electric current is discussed.

The application of electroplastic deformation to form semifinished implants made of the titanium alloy VT6 is considered. It is shown that the use of electroplastic deformation avoids the formation of cracks and increases the strain rate by five times.

A comparative operational testing of the traction-power and controlled operation at the testing ground of JSC Russian Railways was conducted for a 3ES5K series locomotive manufactured in 2021, equipped with axle-by-axle traction control and motor-axial rolling bearings with a locomotive friction activation unit, as well as for a 3ES5K series locomotive with axle-by-axle traction control, without any locomotive friction activation unit (equipped with a standard sand feed). The obtained experimental data are analyzed and systematized, the traction-griping properties of the experimental electric locomotive equipped with a locomotive friction activation unit and the reference electric locomotive without such a unit are compared. Conclusions have been drawn concerning the efficiency of the locomotive friction activation unit under freight traffic conditions in the course of operation at the testing ground at the head of a 7100-е freight train on a section of JSC Russian Railways (even direction).

This article discusses a technology that uses pressure as an additional thermodynamic parameter, which, along with the concentration of alloying elements, temperature, and time, creates a space of variable states for the melt. This allows for the transition of the melt into a strongly nonequilibrium state, significantly increasing the number of possible scenarios for transitioning to a solid state compared to traditional technologies. To achieve the set goals, a control system algorithm has been developed, proposing that the crystallization process be managed according to a model in the coordinate space: temperature, pressure, time. Using the alloy V95 as an example, it was established that, by stopping the process at different stages, alloys with varying combinations of structural and, consequently, physicomechanical properties can be obtained.

The potentialities of widespread application of electric transport, and in particular, tricycles, are demonstrated. By the example of a transporting-and-technological vehicle with a capacity of up to 3 kW, the potentiality of using such vehicles in agriculture is presented. The breadth of application attracts increased attention to the real consumer properties, which has required the development of a set of tests to reveal such properties with subsequently testing a real sample of a cargo electric tricycle. With the use of special equipment, the angles of tipping and sliding, the position of the center of mass, the run duration with a single-charged battery, the traction and velocity parameters, as well as the vibration loading of the machine have been determined. The set of studies has confirmed the efficiency and compliance with the declared characteristics of the machine, as well as the potentiality of its safe operation under year-round loading conditions on different surfaces.

The isothermal elastic-hydrodynamic problem of lubrication of a finite-length radial plain bearing with a partial angle of coverage is considered. The bearing deformations are determined by the finite element method. The shaft deformations are determined from the solution of a plane problem of elasticity theory for a cylinder. It is shown that, under conditions of strong deformations, the minimum thickness of the lubricating layer along the angular coordinate changes significantly in the direction of the bearing axis. In this case, the thickness takes a minimum value at the ends. Families of curves are given that allow estimating the minimum thickness of the lubricating layer at the ends of the bearing after solving the plane problem.

Based on experimental studies aimed at investigating the microstructure and elemental composition of titanium powders for additive machines, obtained by electrodissolution of ОТ4 alloy metal waste in water, it was shown that the rapid crystallization process of molten ОТ4 in a liquid working medium contributes to the spherical shape of the particles, containing the main elements Ti and Al. Spherical titanium powder materials obtained from the electroerosive dispersion of ОТ4 titanium alloy waste can be effectively used for additive machines.

This article discusses methodological, theoretical, and procedural frameworks for studying complex safety issues within the engineering and technical direction of higher education. Based on an analysis of contemporary scientific literature, conclusions are drawn that relevant approaches include: a comprehensive approach reflecting the interrelationship of social aspects and technical systems in the safety of engineering and technological industries; competency-based and knowledge-based approaches aimed at developing students’ ability to apply constructive knowledge, skills, and abilities in engineering activities when creating new products and systems. Significant for studying safety issues is project-oriented education, the “project engineering” approach, and the application and development of morphological methods in technological systems to ensure the development of flexible (interdisciplinary) and professional competencies in engineering education.

The features of brittle fracture of pistons in an internal combustion engine (ICE) of a combined metal have been determined: aluminum cast alloy reinforced with a bandage insert of heat-resistant cast iron. Fractographic analysis of fractures reveals defects in the fusion of the base metal of the pistons and the embedded bandage ring. The cause of the incident is due to the constraint of significant temperature–force deformations during thermal cyclings of a dissimilar metal with different thermal–physical properties and an unsuccessful shape of the cast iron insert. It is complex in nature, combining a low level of piston design and the manufacturing of reinforced castings, in which, during operation, high temperature stresses occur in the metal of the piston and the embedded part.